docs: def list2str(self, l: List, joiner: str) -> str:
          """
          Convert list to str as input for tokenizer
  
          Args:
              l (list): list for converting
              joiner (str): join the elements using this string to separate them.
  
          Returns: the value of the list as a string
  
          """
          result = str()
          for item in l:
              if isinstance(item, list):
                  result = result + self.list2str(item, joiner) + joiner
              elif isinstance(item, dict):
                  result = result + self.dict2str(item, joiner) + joiner
              elif item:
                  result = result + str(item) + joiner
          return result